Reorder rectangle code and fix not rendered inverted rectangle.
Fix Polygon layer to render inverted using normal Cairo commands properly
Rework Layer_PasteCanvas to do not use a separated Cairo context to render its canvas. Also don't untransform the RendDesc. It delivers unneeded large RendDesc in some cases.
When calculate the untransformed RendDesc, do not keep the pixel size but keep the diagonal length in pixels. This would save render time because the number of pixels on the untransformed RendDesc is not higher than the needed for the original one.
When apply a transformation, save and restore the Cairo context. It prevents to apply the layer when it is moved below.
Fix focus effect on Paste Canvas layer for Cairo render